Nature-based systems for rare earth element recovery

A.M. Schmitz, S. Medin, B. Pian, S. Balog-Way
United States

Keywords: critical materials, rare earth elements, biotechnology, genomic engineering, extraction, purification


REEgen is building a clean, climate-smart system for extraction and purification of rare earth elements (REE) and other critical metals using engineered, nature-based processes. We are focusing on recovering REE from secondary sources, such as metallurgical slags and coal combustion residues, to help fill the gap between supply and demand and to promote a circular economy. REEgen’s REE production involves three key steps: bio-extraction, REE-selection, and bio-separations. In bioleaching, microbes convert sugars into a solution of organic acids, called a biolixiviant, that leach metals from a solid matrix. In REE-selection, we use REE-specific ligands to selectively concentrate total REE (tREE). In bio-separations, a series of columns with immobilized bacteria with enhanced affinity for certain REE over others are used to separate REE from each other. All of these processes are based on natural mechanisms that have been optimized through genetic engineering. We are further utilizing genetic engineering to improve efficiency, address commercialization hurdles, and tailor the processes to various input sources. We will present on our genetic improvements to date and outline our path to commercialization of clean rare earth production.